Making metallo-organic compounds



Patented Dec. 28, 1926.

UNITED STATES PATENT. OFFICE.

CHARLES A. KRAUS AND CONE-AL C. GALLIS, 0F WORCESTER, MASSACHUSETTS, AS- SIGNORS TO STANDARD DEVELOPMENT COMPANY, A CORPORATION OF DELAWARE.

MAKING METALLO-ORGANIC COMPOUNDS.

No Drawing.

This invention relates to the art of making metallo-organic compounds, and will be fully understood from the following description. I

Where metallo-organic' compounds, e. g. hydrocarbon compounds of lead or the like, are made by reacting upon the metal by means of hydrocarbon halids under pressure, in large units the operation requires very careful supervision in order to secure the proper control. The tendency is for excess temperature and pressure to develop and this, where occurring, not only cuts down the yield but endangers the apparatus or else occasions loss by blowing the safety valve.

In accordance with the present invention, we proceed along the general lines disclosed in our prior applications, Ser. Nos. 630,089, filed April 5, 1923, and 631,940, filed April 13, 1923 and arrange the conditions of reaction in such manner as to secure a close control upon the reaction. The applications referred to disclose processes involving the reaction between low boiling alkyl halids in vapor phase, for example methyl or ethyl chlorid, and alloys of lead, tin, or the like with an alkali metal. The reaction is conducted under pressure and at a temperature above the normal boiling point of the halid. Preferably, we introduce into the reaction vessel, which advantageously may be of a ball-mill type, the full predetermined charge of lead-alkali metal, lead-sodium or other alloy which is to be used and then start the reaction by introducing a relatively small proportion of the ethyl chlorid or other low boiling hydrocarbon halid.

The alloy is suitably subdivided to go through, say for example a IO-mesh screen,

and it is advisable that care be taken to.

avoid exposure to air or moisture. Thesubdividing may be done in an atmosphere of inert or non-oxidizing character, as nitrogen for instance. If desired, instead of using a separate mill, the alloy may be disintegrated in the final reaction vessel itself, in which case the vessel may also contain a suitable milling or crushing means, or the vessel may be mounted to rotate and be equipped with balls or the like in the manner. of a ballmill, this being particularly advantageous, as subsequently in the reaction theballs can also serve. as agitating and heat transfer means.

Application filed Augusta, 1923. Serial No. 655,752.

ture controlling means, customarily available, may be called into play, but the feature which we particularly emphasize is the provision of reaction control by regulation of the feed of raw material. In practice it is more convenient to initially charge the entire quantity of themetal to be used and then regulate the feed of the hydrocarbon halid. The latter may be conveniently fed from a tank under pressure higher than the operating pressure to be reached in the re-- action chamber, a simple valve control or a balanced diaphragm type of automatic control responsive to the pressure in the reaction chamber being provided. Or where-desilredl, an injector or pump feed can be ap- 1e p The volatile halids," for example ethyl chlorid, if in liquid form when supplied to the reaction vessel, will be vaporized therein owing to the heat generated in the reaction. Although reaction will occur slowly at ordinary temperatures, practically the reaction is started by warming up to about.

35 C. and cooling is subsequently used as may be necessary, the temperature for good results being maintained at about 4070 C., for example. Toward the end the temperature may be allowed to go higher, e. g. O

Pressure in the reaction vessel is caused -by the evolution of vapors from the halid, and in the reaction as normally conducted there is no oubstantial body of liquid halid in contact with the pulverulent alloy. In order to exclude air, an atmosphere of ethyl chlorid or other halid may be formed in the reaction vessel before starting the reaction.

While we have referred to lead tetra'ethyl in describing our invention, it will be understood that we contemplate using the process in connection. with any of the analogous reaction upon a lead-sodium alloy with ethyl chlorid in vapor phase and at a temcompounds of lead with alkyl radicals, or analogous metals such as tin, etc., with corresponding alkyl radicals. While the process is more particularly designed for use with ethyl chlorid, the same procedure is, of course, applicable with other hydrocarbon halides where close reaction control on large scale is desired.

What we claim is:

1. In the art of making lead tetraethyl by perature above the normal boiling point 01 the ethyl chlorid, the improvement which comprises starting chemical reaction upon a charge of lead-sodium'alloy by a relatively small proportion of ethyl chlorid, and controlling the progress of the chemical reaction primarily by further supplying addi tional small proportions of ethyl chlorid.

2. In the art of making lead tetraethyl by reaction upon a lead-sodium alloy with ethyl chloricl in vapor phase and at a temperature above the normal boiling point of the ethyl chlorid, the improvement which comprises controllably chemically reacting upon the lead-sodium alloy by a gradated feed of ethyl chlorid, such gradatcd feed operating as the primary control means for determining the progress of the chemical reaction.

3. In the art of making hydrocarbon compounds of lead by reaction upon an alloy of lead and an alkali metal with an alkyl halid in vapor phase and at a temperature above the normal boiling point of the halid, said halid having a boiling point below average atmospheric temperature, the improvement which comprises chemically reacting upon the alloy by a progressive supply of the halid, such progressive supply operating as the primary means for controlling the chemical reaction.

t. In the art of making alkyl compounds of lead by reaction upon an alloy of lead and an alkali metal with an alkyl chlorid in vapor phase and at a temperature above the normal boiling point of the alkyl chlorid, the improvement which comprises chemically reacting upon the alloy with the alkyl chlorid supplied in regulated quantity in accordance with the progress of the chemical reaction, and operating as the primary means for controlling the progress of that reaction.

CHARLES A.- KRAUS. CONRAL C. CALLIS. 

